Typical brake disc and brake pad damage patterns and

Typical brake disc and brake
pad damage patterns and
their root causes
www.meyle.com
Good brakes save lives!
The consequences of choosing the wrong or low-grade brake
parts can be dramatic. Only use the brake components specified
for the given vehicle application. Brake system repairs may only be
performed by skilled and trained personnel. Adhere to the vehicle
or brake manufacturer‘s specifications at all times.
When installing new brake components, observe the
following:
>
>
>
>
>
lways replace brake pads along with brake discs.
A
Always replace all brake discs and pads per axle.
Be careful to bed in new brake discs and pads properly.
Avoid unnecessary heavy braking on the first 200 kilometres.
Brake performance may be lower on the first 200 driven
kilometres.
Check for functional reliability after installation:
> P
ump brake pedal until it becomes stiff.
> Pedal travel must not vary at constant pedal load after pedal has
been depressed several times.
> Check wheels for free rotation.
> Check brake fluid level in expansion tank and top up, if required.
> Perform check stops.
MEYLE Platinum Disc:
All-new finish. No degreasing.
Fit and go.
All MEYLE brake discs come as ready-to-mount assemblies, most of
them featuring the locating screw. They do not require degreasing
and are resistant to rim cleaners. Cutting-edge paint technology
made in Germany provides MEYLE Platinum Discs with long-term
anti-corrosion protection while adding a brilliant appearance.
Further refinement of the tried-and-tested MEYLE finish has led to
environmentally-friendly production processes.
MEYLE Platinum Discs – the safety solution engineered by one
of the industry‘s leading experts in coated brake discs.
www.meyle.com
Overheating of the mating
friction surfaces
Score and groove marks
on disc brakes
The problem:
The problem:
Brake pad fails to disengage and rubs against the disc. This can
cause the brake system to overheat.
Score and groove marks on brake disc friction surfaces.
Causes:
>
>
>
>
>
> Brake pad seized
> Brake piston stuck in calliper
> Driving with depressed brake pedal, e.g. when going downhill
Possible consequences:
Causes:
F oreign objects between brake disc and pad (dirt, road salt, etc.)
Corrosion
Overly soft brake discs
Low-grade brake brake pad material
Excessive strain on brake system
> R
educed brake performance due to vitrification of the brake pad
surface
> Unpleasant noise
> Brake disc deformation resulting in brake wobble and brake
judder
> In the worst case, the brake disc friction surface may peel off
Possible consequences:
MEYLE‘s advice:
MEYLE‘s advice:
Use mounting paste and ensure all parts move freely during
installation. Avoid unnecessary disc brake drag.
Ensure brake system is free of foreign objects during installation.
Use high-quality brake components from MEYLE. Replace brake
pads along with brake discs!
> Limited/reduced braking power
> Unpleasant noise
Corrosion
Wheel hub run-out
The problem:
The problem:
Severe rust formation on brake discs and pads.
Asymmetrical wear of brake disc front and rear sides. Formation of
bluish-black hotspots.
Causes:
>
>
>
>
limatic effects (e.g. road salt, moisture)
C
Extended periods of downtime with parking brake engaged
Brake piston stuck in calliper
Brake piston not fully returned to retracted position
Causes:
> B
rake disc fails to fit flush against wheel hub
> M
isalignment of functional axes
> W
heel hub misalignment in relation to brake calliper
Possible consequences:
Possible consequences:
>
>
>
>
>
>
>
>
ibration and brake judder caused by brake disc deposits
V
Noise generation
Reduced braking power
Overheating of brake discs and pads caused by rust spots
P
ulsing brake pedal/judder
S haking steering wheel
R
educed braking power
W
ear limit reached prematurely
MEYLE‘s advice:
MEYLE‘s advice:
Avoid extended periods of vehicle downtime with parking brake
continually engaged. Ensure all components are free-moving.
After extended periods of downtime cautiously apply the brakes to
unlock the brake system and ensure rust spots have been removed.
Brake discs must be installed clean, dry and degreased. Check wheel
hub for true running prior to brake disc installation.
NOTE: Any existing wheel hub run-out is doubled owing to the
larger brake disc diameter. Using a dial gauge with adjustable
magnetic base allows you to check for installation-induced run-out
directly on the car instead of performing a test drive.
Asymmetrical wear of brake
disc front and rear sides
Contaminated mounting
face, pressure marks and
corrosion
The problem:
The problem:
Brake pad is pressed unevenly against brake disc.
Plane-parallel installation is not or not fully possible.
Causes:
Causes:
>
>
>
>
> F ailure to clean wheel hub mounting face correctly
> D
irt or rust particles trapped between brake disc and hub
> G
rease/paste form foreign objects trapped between brake disc
and wheel hub
Brake pad seized
Problems during installing
Anti-squeal shims out of place
Brake calliper positioned incorrectly
Possible consequences:
>
>
>
>
>
>
symmetrical wear of brake disc front and rear sides
A
Reduced braking power
Pulsing brake pedal/judder
Shaking steering wheel
Possible noise generation
Wear limit reached prematurely
Possible consequences:
>
>
>
>
>
A
symmetrical wear
P
ulsing brake pedal/judder
S haking steering wheel
R
educed braking power
W
ear limit reached prematurely
MEYLE‘s advice:
MEYLE‘s advice:
Ensure all components are free-moving. Ensure correct positioning
of brake calliper. Observe mounting instructions.
Mounting face must be clean, dry and rust-free. Check wheel hub
for true running/run-out prior to brake disc installation. Using a
dial gauge with adjustable magnetic base allows you to check
for installation-induced run-out directly on the car instead of
performing a test drive.
Mounting face cracked
around bores
The problem:
Formation of cracks in area surrounding wheel bolt holes.
Causes:
> E xcessive torque to tighten wheel nuts and bolts
> F ailure to tighten wheel nuts and bolts in correct order
> L ack of plane-parallel alignment between wheel hub and
brake disc
Possible consequences:
> B
rake disc shakes immediately after installation
> M
ounting face deformation (cracks might not be visible)
> B
rake disc cracks under load
MEYLE‘s advice:
Adhere to tightening torques and sequences specified by the
manufacturer. Ensure plane-parallel installation. Using a dial gauge
with adjustable magnetic base allows you to check for installationinduced run-out directly on the car instead of performing a test
drive.
We make braking a safe experience.
MEYLE Platinum Pads offer maximum driving comfort
to exclusive standards.
Specially designed to suit the needs of luxury models, SUVs
and light commercial vehicles (LCVs) MEYLE brake pads set the
benchmark in premium brake technology. Dispensing with copper
and heavy-metal compounds MEYLE Platinum Pads offer a bestin-class friction coefficient. Outstanding responsiveness and stable
braking even at high temperatures along with extremely low noise
levels are the key features which put the latest generation of MEYLE
brake discs in a class of their own. MEYLE Platinum Pads ensure short
braking distances and stable braking in any situation.
Naturally, MEYLE Platinum Pads are ECE R90 type-approved
and virtually all are fitted with MEYLE 3L shims.
www.meyle.com
Your source for MEYLE parts:
1571.en
4 040074 143476
Caution:
>
These instructions are for information purposes
only and are no substitute for the specifications
of the vehicle manufacturers.
>
Repairs may only be performed by properly
trained staff.
Wulf Gaertner Autoparts AG
Merkurring 111 • 22143 Hamburg • Germany
[email protected] • www.meyle.com